page_title: Spinophorosaurus
section_title: Palaeobiology
hierarchical_section_title: Spinophorosaurus / Palaeobiology
caption_attribution_description: Dentary tooth of Spinophorosaurus nigerensis, lingual view (Paratype, NMB-1698-R).
context_page_description: Spinophorosaurus is a genus of sauropod dinosaur that lived in what is now Niger during the Middle Jurassic period. The first two specimens were excavated in the 2000s by German and Spanish teams under difficult conditions. The skeletons were brought to Europe and digitally replicated, making Spinophorosaurus the first sauropod to have its skeleton 3D printed, and were to be returned to Niger in the future. Together, the two specimens represented most of the skeleton of the genus, and one of the most completely known basal sauropods of its time and place. The first skeleton was made the holotype specimen of the new genus and species Spinophorosaurus nigerensis in 2009; the generic name refers to what was initially thought to be spiked osteoderms, and the specific name refers to where it was found. A juvenile sauropod from the same area was later assigned to the genus.
  The subadult holotype specimen is estimated to have been around 13 m in length, whereas the paratype was about 14 m long. The shoulder height reached by these individuals was estimated at around 4 m, and the weight at about 7 metric tons.
context_section_description: Spinophorosaurus and some other sauropodomorphs did not have reduced vestibular apparatuses, a sensory system for balance and orientation in the inner ear, though this might have been expected in a lineage that led to heavy, plant-eating quadrupeds. It is unknown why Spinophorosaurus retained this feature, but the size and morphology of sauropodomorph labyrinths may be related to neck length and mobility, for example. It is possible expansion of the vestibular apparatus is an indicator of the importance of vision and coordinated eye, head, and neck movements, though interpretation of sauropod vestibular features are still uncertain.
  At a 2018 conference, Benjamin Jentgen-Ceschino and colleagues reported radial fibrolamellar bone (RFB), a type of bone tissue characterised by radially oriented channels, in the outermost part of the cortex (the outermost bone layer) of the humerus belonging to an adult Spinophorosaurus specimen and a young adult Isanosaurus. Normally, the cortex in the long bones of sauropods shows a fibrolamellar complex instead. RFB is considered to be fast growing bone tissue, and has not been reported in sauropods before. Its presence in the outermost cortex is unusual, as it would usually be expected in the innermost cortex (corresponding to juvenile growth). The RFB of the Spinophorosaurus was buried in the outer cortex, followed by a normal fibrolamellar complex, which indicates the animal survived for some time after its accelerated growth, which probably suggests pathological bone growth due to injury.
caption: Dentary tooth of the paratype; note the enlarged, spaced denticles near the top of the crown
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